The present invention relates to a digital data transmission method for transmitting digital data of differing resolution, a digital data transmission device suitable for implementing this transmission method, and a digital data reception device for receiving transmitted digital data.
Recently, image and sound compression methods based on MPEG (Moving Picture Experts Group) standards have come to be used, and the methods described in ISO/IEC13818-1, 1383818-2, 13818-3 are commonly known. Furthermore, with regard to broadcast methods, in Japan, CS digital broadcast systems and CATV digital transmission systems are stipulated by Finding No.74 of the Electrical Communications Technology Commission.
With regard to animated image encoding methods, the Main Profile/Main Level (MP@ML) method described in ISO/IEC13818-2 involves compression encoding of a signal running up to a maximum of 30 frames/second based on a sequential scanning system (progressive) or an interlaced scanning system, and this is suitable for conventional television broadcast.
FIG. 32 is a diagram showing the composition of transmission data in a conventional transmission method for image data.
In this example, image data for program number 1 and program number 3 in a band centred on a reception frequency of 12.568 GHz is superimposed with NIT (network information table), PMT (program maintenance table), and EIT (event information table), in packet units. The data structure in these packets and the standards for their multiplexing are stipulated in detail by ISO/IEC13818-1, 13818-2, 13818-3 and Finding No.74 of the Electrical Communications Technology Commission.
In this diagram, numeral 17 is a packet of image data for program number 1, and by defining its leading packet identifier PID as 0x91, it is possible for this packet to be recognized as an image data packet for program number 1. Numeral 18 is an image data packet for program number 3, and by defining its leading packet identifier PID as 0x93, it is possible for this packet to be recognized as an image data packet for program number 3.
Numeral 19 is an NIT (network information table) packet, which defines the frequency at which the image data relating to program number 1 and program number 3 is transmitted. In the present example, it indicates that the image data for program number 1 and program number 3 is superimposed in the 12.568 GHz band, as described above.
Numeral 20 is a PMT (program maintenance table) packet and in the present example, it indicates that the packet identifier for the program number 1 image data is contained in packet 0x91, and the packet identifier for the program number 3 image data is contained in packet 0x93.
Numeral 21 is an EIT (event information table) packet which is a table of the program contents. In the present example, it shows that program number 1 will be broadcasting baseball a between 19:00-20:00, a quiz between 20:00-21:00, and a foreign film from 21:00 onwards, whilst program number 3 will be broadcasting baseball a between 19:00-20:00, soccer between 20:00-21:00, baseball b between 21:00-22:00, and news from 22:00 onwards.
FIG. 33 is a compositional diagram of a conventional transmission device 45 and reception device 46 for image data. In the diagram, numeral 47 denotes compression encoding means, which compresses and encodes an input digital video signal, in this case, for example, an interlaced scanning signal or a sequential scanning signal running at 30 frames or less, in accordance with ISO/IEC138318-2. Numeral 48 denotes multiplexing means for multiplexing the image data for program number 1 and program number 3, and numeral 49 denotes modulating means for performing modulation, such as QPSK, or the like.
Numeral 50 denotes demodulating means for demodulating information containing at the least image data multiplexed and transmitted in order to broadcast programs, and in FIG. 32, demodulating means 50 demodulates image data for program number 1, image data for program number 3, NIT, PMT and EIT. Numeral 51 denotes separating means for separating information containing image data demodulated by demodulating means 50. 52 denotes program selecting means, which receives a program selection control made by the operator (user) and indicates the selected program to the demodulating means 50 and separating means 51. Examples of program selecting means 52 include commonly and widely used devices, such as a remote control device for selecting television programs, or channel selection by television channel buttons or a PC mouse. Numeral 53 denotes image decoding means for decoding image data separated by separating means 51, which in the present example involves a bit stream encoded by an MP@ML system, and outputting this data in the form of a video signal to image display means 54.
In addition to these elements, a standard image data reception device also requires various components, such as a decoding section for decoding sound data, for example, but since these components do not relate directly to the present invention, a description thereof is omitted here.
Below, the operation of a conventional transmission and reception device constituted as described above is described.
Firstly, when program selecting means 52 receives a program selection control from the operator, it indicates the selected program to demodulating means 50. Demodulating means 50 then demodulates the image data for the designated channel. Separating means 51 separates the image data in the information demodulated by demodulating means 50 on the basis of the instruction from program selecting means 52.
In specific terms, if an instruction is given indicating that the data for program number 1 is to be reproduced, then the value of the packet identifier 0x91 of the image data in program number 1 is obtained from the PMT value, and the packet having packet identifier 0x91 is extracted and transferred to subsequent processing. Furthermore, if an instruction is given indicating that the data for program number 3 is to be reproduced, then the value of the packet identifier 0x93 of the image data in program number 3 is obtained from the PMT value, and the packet having packet identifier 0x93 is extracted and transferred to subsequent processing.
Image decoding means 53 decodes the image data separated by separating means 51 and outputs this data in the form of a video signal.
(Technical Problems to be Solved by the Invention)
Recently, attention has started to focus on animated images having higher resolution than interlaced scanning signals or sequential scanning signals operating at 30 frames or less and compression encoded by a conventional Main Profile/Main Level (MP@ML) method, as described above. In this case, the frame number may be, for example, 59.94 frames/seconds, namely, twice the NTSC frame rate, and systems conforming to main profile H14 (MP@H14) in ISO/IEC13818-2 have been envisaged.
Therefore, it is anticipated that, in the future, low-resolution image data and high-resolution image data will be multiplexed and broadcast simultaneously by hierarchical encoding, and moreover, hierarchical encoded data and non-hierarchical encoded data will be multiplexed and broadcast simultaneously. However, in a conventional composition as described above, it is not possible to identify between hierarchical encoding and non-hierarchical encoding, or between low-resolution image data and high-resolution image data, so if it is supposed that MP@ML image data is multiplexed and transmitted with image data relating to a sequential scanning signal of image size 704xc3x97480 and operating at a higher frame frequency than MP@ML, for example, 59.94 frames, then although the frame number will be 59.94 frames/seconds, which is twice the frame rate of NTSC, for example, and the signal will conform to Main Profile H14 (MP@H14), since the image size is small it will be given a subset positioning and when decoded by the aforementioned image decoding means 53, it will not be decoded properly since it exceeds the capacity of the image decoding means 53, and hence a correct image signal will not be output and malfunction will occur.
Moreover, as shown in FIG. 34, in a program table displayed by a conventional image data reception device 46, it is not possible to distinguish between programs having image data of different resolutions, when low-resolution image data and high-resolution image data is broadcast simultaneously by multiplexing. Therefore, the operator is able is select a program number having high-resolution image data which cannot be decoded, and if this occurs, the signal will not be properly decoded and a distorted image will be output, which the operator may identify to be a malfunction.
In this way, in the prior art, if digital data of different resolutions is transmitted by multiplexing, then since the high-resolution digital data cannot be decoded correctly, a distorted image is output, causing confusion and inconvenience to the operator during use, and providing an image content which is not intended by the program supplier.
The present invention was devised with the foregoing in view, an object thereof being to provide a digital data transmission method and digital data transmission device whereby digital data is transmitted such that the receiving side can identify whether it is hierarchically encoded or non-hierarchically encoded, and digital data of differing resolutions can be reproduced correctly at the receiving side, thereby increasing the freedom of program composition.
It is a further object of the present invention to provide a digital data reception device which does not cause problems, such as confusing the operator, when digital data of differing resolutions is transmitted by multiplexing, even if the reception device is capable of decoding one type of digital data only, and moreover, to provide a digital data reception device whereby a first digital data and second digital data can be received and reproduced correctly.
(Means for Solving the Problems)
In order to achieve the aforementioned objects, the present invention is constituted in the following way.
Namely, in the present invention, a low-resolution digital video signal and a high-resolution digital video signal are generated from an input digital video signal by means of hierarchical encoding, and when the first and second digital data obtained by encoding the two digital video signals is divided into packet units and then multiplexed and transmitted with packets containing information relating to programs, identification information for identifying the first digital data and the second digital data is given in the packets containing information relating to the programs.
By means of the present invention, the receiving side is able to identify the first and second digital data on the basis of the identification information described in the packets containing information relating to programs, thereby enabling the low-resolution digital video signal and the high-resolution digital video signal to be reproduced correctly and hence allowing the variety of programs transmitted to be increased.
A first aspect of the present invention is a method for generating a low-resolution digital video signal by frequency scaling of an input digital video signal. dividing first digital data obtained by encoding the low-resolution digital video signal and second digital data obtained by encoding the input digital video signal into packet units, respectively, and multiplexing and transmitting the data with packets containing information relating to programs, wherein identification information for identifying non-hierarchical encoding and hierarchical encoding is described in the packets containing information relating to programs, thereby enabling the receiving side to identify whether data is non-hierarchically encoded or hierarchically encoded on the basis of the identification information.
A second aspect of the present invention is a method for generating a high-resolution digital video signal by frequency scaling of an input digital video signal, dividing second digital data obtained by encoding the high-resolution digital video signal and first digital data obtained by encoding the input digital video signal into packet units, respectively, and multiplexing and transmitting the data with packets containing information relating to programs, wherein identification information for identifying non-hierarchical encoding and hierarchical encoding is described in the packets containing information relating to programs, thereby enabling the receiving side to identify whether data is non-hierarchically encoded or hierarchically encoded on the basis of the identification information.
A third aspect of the present invention is a method for dividing first digital data obtained by encoding a digital video signal generated from an input digital video signal by means of a low-pass filter and second digital data obtained by encoding a digital video signal generated from the input digital video signal by means of a high-pass filter in packet units, respectively, and multiplexing and transmitting the data with packets containing information relating to programs, wherein identification information for identifying non-hierarchical encoding and hierarchical encoding is described in the packets containing information relating to programs, thereby enabling the receiving side to identify whether data is non-hierarchically encoded or hierarchically encoded on the basis of the identification information.
A fourth aspect of the present invention is a method for generating a low-resolution digital video signal by frequency scaling of an input digital video signal, dividing first digital data obtained by encoding the low-resolution digital video signal and second digital data obtained by encoding the input digital video signal into packet units, respectively, and multiplexing and transmitting the data with packets containing information relating to programs, wherein identification information for identifying the first digital data and the second digital data is described in the packets containing information relating to programs, thereby enabling the receiving side to identify the first and second digital data on the basis of the identification information. Furthermore, since a low-resolution digital video signal is generated and transmitted by frequency scaling of a high-resolution input digital video signal, it is possible to receive and reproduce a low-resolution digital video signal at the receiving side, even using a relatively inexpensive low-resolution receiving device.
A fifth aspect of the present invention is a method for generating a high-resolution digital video signal by frequency scaling of an input digital video signal, dividing second digital data obtained by encoding the high-resolution digital video signal and first digital data obtained by encoding the input digital video signal into packet units, respectively, and multiplexing and transmitting the data with packets containing information relating to programs, wherein identification information for identifying the first digital data and the second digital data is described in the packets containing information relating to programs, thereby enabling the receiving side to identify the first and second digital data on the basis of the identification information and to reproduce correctly a low-resolution digital video signal and a high-resolution digital video signal. Moreover, since the input digital video signal has low resolution, the transmitting system can be composed relatively inexpensively, but since a high-resolution digital video signal is generated and transmitted by frequency scaling of a low-resolution input digital video signal, high-resolution images can still be received and reproduced using a high-resolution reception device.
A sixth aspect of the present invention is a method for dividing first digital data obtained by encoding a digital video signal generated from an input digital video signal by means of a low-pass filter and second digital data obtained by encoding a digital video signal generated from the input digital video signal by means of a high-pass filter in packet units, respectively, and multiplexing and transmitting the data with packets containing information relating to programs, wherein identification information for identifying the first digital data and the second digital data is described in the packets containing information relating to programs, thereby enabling the receiving side to identify the first and second digital data on the basis of the identification information and reproduce a digital video signal correctly.
A seventh aspect of the present invention is the invention according to any of the fourth to sixth aspects, wherein decoding programs for decoding at least one of the first digital data and the second digital data are divided into packet units and multiplexed with the packets containing information relating to programs, thereby enabling the decoding programs to be changed readily at the transmitting side in response to technological advances, or the like.
An eighth aspect of the present invention is the invention according to any of the first to seventh aspects, wherein the packets containing information relating to programs form a program management table showing which program is transmitted by which packet, thereby enabling the receiving side to identify non-hierarchical encoding and hierarchical encoding, or the first and second digital data, on the basis of the identification information in this program management table, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly. Moreover, by using a program management table in this way, it is possible to change the resolution used in transmission, in program number units.
A ninth aspect of the present invention is the invention according to any of the first to seventh aspects, wherein the packets containing information relating to programs form a program contents table showing the contents of programs, thereby enabling the receiving side to identify non-hierarchical encoding or hierarchical encoding, or the first and second digital data, on the basis of the identification information in this program contents table, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly. By using a program contents table in this way, it is possible to change the resolution used in transmission, in program units.
A tenth aspect of the present invention is the invention according to any of the first to seventh aspects, wherein the packets containing information relating to programs form a network information table showing which programs are broadcast by which channel, thereby enabling the receiving side to identify non-hierarchical encoding or hierarchical encoding, or the first and second digital data, on the basis of the identification information in this network information table, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly. By using a network information table in this way, it is possible to change the resolution used in transmission, for each network, in other words, for each transponder.
An eleventh aspect of the present invention is a digital data transmission device comprising: hierarchical encoding means for generating a low-resolution digital video signal by frequency scaling of an input digital video signal and outputting first digital data obtained by encoding the low-resolution digital video signal, as well as outputting second digital data obtained by encoding the input digital video signal; identification information generating means for generating identification information for identifying non-hierarchical encoding and hierarchical encoding; and multiplexing means for dividing the first digital data and the second digital data into packet units and multiplexing the data with packets containing information relating to programs; wherein the identification information is described in the packets containing information relating to programs, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data on the basis of the identification information.
A twelfth aspect of the present invention is a digital data transmission device comprising: hierarchical encoding means for generating a high-resolution digital video signal by frequency scaling of an input digital video signal and outputting second digital data obtained by encoding the high-resolution digital video signal, as well as outputting first digital data obtained by encoding the input digital video signal; identification information generating means for generating identification information for identifying non-hierarchical encoding and hierarchical encoding; and multiplexing means for dividing the first digital data and the second digital data into packet units and multiplexing the data with packets containing information relating to programs; wherein the identification information is described in the packets containing information relating to programs, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data on the basis of the identification information.
A thirteenth aspect of the present invention is a digital data transmission device comprising: hierarchical encoding means for outputting first digital data obtained by encoding a digital video signal generated from an input digital video signal by means of a low-pass filter and second digital data obtained by encoding a digital data generated from the input digital video signal by means of a high-pass filter; identification information generating means for generating identification information for identifying non-hierarchical encoding and hierarchical encoding; and multiplexing means for dividing the first digital data and the second digital data into packet units and multiplexing the data with packets containing information relating to programs; wherein the identification information is described in the packets containing information relating to programs, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data on the basis of the identification information.
A fourteenth aspect of the present invention is a digital data transmission device comprising: hierarchical encoding means for generating a low-resolution digital video signal by frequency scaling of an input digital video signal and outputting first digital data obtained by encoding the low-resolution digital video signal, as well as outputting second digital data obtained by encoding the input digital video signal; identification information generating means for generating identification information for identifying the first digital data and the second digital data; and multiplexing means for dividing the first digital data and the second digital data into packet units and multiplexing the data with packets containing information relating to programs; wherein the identification information is described in the packets containing information relating to programs, thereby enabling the receiving side to identify the first and second digital data on the basis of the identification information, such that the low-resolution digital video signal and the high-resolution digital video signal can be reproduced correctly. Moreover, since the low-resolution digital video signal is generated and transmitted by frequency scaling of a high-resolution input digital video signal, it is possible to reproduce a low-resolution digital video signal at the receiving side using an inexpensive or reception device.
A fifteenth aspect of the present invention is a digital data transmission device comprising: hierarchical encoding means for generating a high-resolution digital video signal by frequency scaling of an input digital video signal and outputting second digital data obtained by encoding the high-resolution digital video signal, as well as outputting first digital data obtained by encoding the input digital video signal; identification information generating means for generating identification information for identifying the first digital data and the second digital data; and multiplexing means for dividing the first digital data and the second digital data into packet units and multiplexing the data with packets containing information relating to programs; wherein the identification information is described in the packets containing information relating to programs, thereby enabling the receiving side to identify the first and second digital data on the basis of the identification information, such that the low-resolution digital video signal and the high-resolution digital video signal can be reproduced correctly.
A sixteenth aspect of the present invention is a digital data transmission device comprising: hierarchical encoding means for outputting first digital data obtained by encoding a digital video signal generated from an input digital video signal by means of a low-pass filter and second digital data obtained by encoding a digital data generated from the input digital video signal by means of a high-pass filter; identification information generating means for generating identification information for identifying the first digital data and the second digital data; and multiplexing means for dividing the first digital data and the second digital data into packet units and multiplexing the data with packets containing information relating to programs; wherein the identification information is described in the packets containing information relating to programs, thereby enabling the receiving side to identify the first and second digital data on the basis of the identification information, such that a digital video signal can be reproduced correctly.
A seventeenth aspect of the present invention is the invention according to any of the fourteenth to sixteenth aspects, comprising decoding program generating means for generating decoding programs for decoding at least one of the first digital data and the second digital data, the decoding programs being divided into packet units and multiplexed with the packets containing information relating to programs, thereby enabling the decoding programs to be changed readily at the transmitting side in response to technological advances, or the like.
An eighteenth aspect of the present invention is the invention according to any of the eleventh to seventeenth aspects, wherein the packets containing information relating to programs form a program management table showing which program is transmitted by which packet, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data, or first and second digital data, on the basis of the identification information in the program management table, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly. Furthermore, by using a program management table in this way, the resolution used in transmission can be changed in program number units.
A nineteenth aspect of the present invention is the invention according to any of the eleventh to seventeenth aspects, wherein the packets containing information relating to programs form a program contents table showing the contents of programs, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data, or first and second digital data, on the basis of the identification information in the program contents table, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly. Furthermore, by using a program contents table in this way, the resolution used in transmission can be changed in program units.
A twentieth aspect of the present invention is the invention according to any of the eleventh to seventeenth aspects of the invention, wherein the packets containing information relating to programs form a network information table showing which programs are broadcast by which channel, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data, or first and second digital data, on the basis of the identification information in the network information table, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly. Furthermore, by using a network information table in this way, the resolution used in transmission can be changed for each network, in other words, for each transponder.
A twenty-first aspect of the present invention is the invention according to the eighteenth aspect of the present invention, wherein the identification information is described in a system control identifier of a program information descriptor in the program management table, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data, or first and second digital data, on the basis of the identification information in the system control identifier, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly.
A twenty-second aspect of the present invention is the invention according to the eighteenth aspect, wherein the identification information is described in a stream identifier of a program information descriptor in the program management table, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data, or first and second digital data, on the basis of the identification information in the stream identifier, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly.
A twenty-third aspect of the present invention is the invention according to the nineteenth aspect, wherein the identification information is described in a component identifier indicating image data attributes in the program contents table, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data, or first and second digital data, on the basis of the identification information in the component identifier, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly.
A twenty-fourth aspect of the present invention is the invention according to the nineteenth aspect, wherein the identification information is described as a program information correspondence table showing the correspondence between program information and packet identifiers in the program contents table, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data, or first and second digital data, on the basis of the identification information in the program information correspondence table, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly.
A twenty-fifth aspect of the present invention is the invention according to the twentieth aspect, wherein the identification information is described in a network identifier for identifying the network transmitting the image data in the network information table, thereby enabling the receiving side to identify non-hierarchically encoded data and hierarchically encoded data, or first and second digital data, on the basis of the identification information in the network identifier, such that the low-resolution digital video signal and high-resolution digital video signal can be reproduced correctly.
A twenty-sixth aspect of the present invention is the invention according to any of the fourteenth to twenty-fifth aspects, wherein charge information relating to the first digital data and the second digital data is transmitted supplementarily, thereby enabling the charge situation to be understood at the receiving side.
A twenty-seventh aspect of the present invention is the invention according to any of the eleventh to twenty-sixth aspects, wherein the first digital data is a signal obtained by compression encoding of a sequential scanning signal operating at 720 maximum effective horizontal pixels, 480 maximum effective vertical scanning lines, and a maximum frame rate of 60 frames/second, thereby enabling a low-resolution image to be displayed by means of a sequential scanning signal operating at 720 maximum effective horizontal pixels, 480 maximum effective vertical scanning lines, and a maximum frame rate of 60 frames/second.
A twenty-eighth aspect of the present invention is a digital data reception device for receiving a signal transmitted by multiplexing first digital data and second digital data, obtained by encoding a low-resolution digital video signal and a high-resolution digital video signal, with identification information for identifying both of the digital data, and reproducing the low-resolution digital video signal and the high-resolution digital video signal, comprising: demodulating means for demodulating the first digital data, the second digital data and information containing the identification information; separating means for separating and extracting digital data corresponding to a program selection operation on the basis of the identification information and the program selection operation; low-resolution decoding means for decoding first digital data separated and extracted by the separating means and outputting the data as a low-resolution digital video signal; and high-resolution decoding means for decoding second digital data separated and extracted by the separating means and outputting the data as a high-resolution digital video signal, thereby enabling the first and second digital data and identification information to be demodulated, such that a selected low-resolution digital video signal or high-resolution digital video signal can be reproduced correctly.
A twenty-ninth aspect of the present invention is a digital data reception device for receiving a signal transmitted by multiplexing first digital data and second digital data, obtained by encoding a low-resolution digital video signal and a high-resolution digital video signal, with identification information for identifying both the digital data and a first and a second decoding program for decoding both the digital data, respectively, and reproducing the low-resolution digital video signal and the high-resolution digital video signal, comprising: demodulating means for demodulating the first and second digital data, and information containing the identification information and the first and second decoding programs; separating means for separating and extracting digital data and a decoding program corresponding to a program selection operation, on the basis of the identification information and the program selection operation; low-resolution computing means for decoding first digital data separated and extracted by the separating means in accordance with the first decoding program and outputting the data as a low-resolution digital video signal; and high-resolution computing means for decoding second digital data separated and extracted by the separating means in accordance with the second decoding program and outputting the data as a high-resolution digital video signal, thereby enabling the first and second digital data and identification information to be demodulated such that a selected low-resolution digital video signal or high-resolution digital video signal can be reproduced correctly on the basis of the program selection operation and the identification information, whilst also allowing the decoding programs to be changed readily on the transmitting side in response to technological advances, or the like.
A thirtieth aspect of the present invention is a digital data reception device for receiving a signal transmitted by multiplexing first digital data and second digital data, obtained by encoding a low-resolution digital video signal and a high-resolution digital video signal, with identification information for identifying both the digital data, and reproducing the low-resolution digital video signal, comprising: demodulating means for demodulating the first digital data, the second digital data and information containing the identification information; separating means for separating and extracting digital data corresponding to a program selection operation on the basis of the identification information and the program selection operation; low-resolution decoding means for decoding first digital data separated and extracted by the separating means and outputting the data as a low-resolution digital video signal; and prohibiting means for prohibiting decoding of second digital data separated and extracted by the separating means, thereby preventing display of distorted reproduced images, since decoding is not carried out if the high-resolution digital video signal is selected by the program selection operation.
A thirty-first aspect of the present invention is a digital data reception device for receiving a signal transmitted by multiplexing first digital data and second digital data, obtained by encoding a low-resolution digital video signal and a high-resolution digital video signal, with identification information for identifying both the digital data and a program contents table showing the contents of programs at different times and the contents of the digital data constituting each program, and reproducing a selected program, comprising: program table creating means for creating a program table showing the contents of programs at different times and indicating whether the digital data constituting each program is the first digital data or second digital data, on the basis of the program contents table and the identification information, the program table created being displayed on image display means, thereby enabling an operator (user) to select a program to be reproduced, on the basis of the program table.
A thirty-second aspect of the present invention is the invention according to the thirty-first aspect, wherein the programs relating to the first digital data or the programs relating to the second digital data are displayed as a program table, thereby preventing the operator from selecting a program which cannot be received and reproduced, by displaying a program table showing only programs having a low-resolution digital video signal in low-resolution reception devices which can only receive and reproduce low-resolution digital video signals.
A thirty-third aspect of the present invention is the invention according to any of the twenty-eighth to thirty-second aspects, wherein the first digital data is a signal obtained by compression encoding of a sequential scanning signal operating at 720 maximum effective horizontal pixelsxc3x97480 effective vertical scanning lines and a maximum frame rate of 60 frames/second, thereby enabling a low-resolution image to be displayed by means of a sequential scanning signal operating at 720 maximum effective horizontal pixelsxc3x97480 effective vertical scanning lines and a maximum frame rate of 60 frames/second.